The United States Environmental Protection Agency has said that indoor air may be two to five times more polluted than outdoor air. This conclusion raises obvious health concerns, and suggests that appropriate steps should be taken to address this issue. The primary defense mechanism for building occupants is effective filtration utilized in conjunction with the structures HVAC (Heating, Ventilating and Air Conditioning) equipment. The filtration is generally utilized at the inlet to the HVAC system. However, dust, mold or other particulate matter may be present or accumulate in the ducting system, past the inlet filter. Thus these substances may be discharged through the interior outlets of the HVAC system, providing a potential health hazard to the building occupants. One manner of addressing this problem is by filtering the air discharged at the HVAC outlet.